Sensors are utilized in numerous industrial applications for measuring and monitoring phenomena. In many applications, multiple sensors can be utilized in conjunction with a system, but connecting all of the sensors with their associated communication wires to a central panel can present many reliability issues, space challenges, interference, and other issues. To address some of these challenges and issues, sensors and intelligent electronic devices (IEDs) have been developed that can communicate over serial bus, Ethernet, etc., where the measured data can be digitized, time-stamped, formatted for communication, and sent through the data channel or network, eliminating many unnecessary cables.
In many cases, time stamps are applied to the data by the local sensors or IEDs. However, when the local clocks or time sources that provide the time stamps are not synchronized to a global time source, the received data, when re-assembled according to time stamps, can present an inaccurate representation of the monitored phenomena.
Synchronizing local time sources to reduce time stamp error associated with each sensor or IED may be possible, but it can be prohibitively expensive. For example, a broadcast global positioning system (GPS) signal may be received by sensors or IEDs for synchronization of each component's associated time source, but the GPS receivers may cost more than the sensors, or there may be line-of-sight restrictions that prohibit reception of the synchronization signals. High quality crystals may be utilized with local time sources, but drift over time can still be an issue that can cause loss of time-synchronization.